﻿using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Web.Mvc;

namespace Controllers
{
    public class CodeController: Controller
    {
        [Route("code")]
        public void Index()
        {
            var w = Request.QueryString["w"];
            var h = Request.QueryString["h"];

            int codeW = 80;
            if (!string.IsNullOrEmpty(w))
            {
                codeW = Convert.ToInt32(w);
            }
            int codeH = 22;
            if (!string.IsNullOrEmpty(h))
            {
                codeH = Convert.ToInt32(h);
            }

            int fontSize = codeH / 2 > 16 ? codeH / 2 : 16;//16;
            string chkCode = string.Empty;
            //颜色列表，用于验证码、噪线、噪点 
            Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };
            //字体列表，用于验证码 
            string[] font = { "Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" };
            //验证码的字符集，去掉了一些容易混淆的字符 
            char[] character = { '2', '3', '4', '5', '6', '8', '9', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };
            Random rnd = new Random();
            //生成验证码字符串 
            for (int i = 0; i < 4; i++)
            {
                chkCode += character[rnd.Next(character.Length)];
            }
            //写入Session
            Session["code"] = chkCode;
            //创建画布
            Bitmap bmp = new Bitmap(codeW, codeH);
            Graphics g = Graphics.FromImage(bmp);
            g.Clear(Color.White);
            //画噪线 
//            for (int i = 0; i < 5; i++)
//            {
//                int x1 = rnd.Next(codeW);
//                int y1 = rnd.Next(codeH);
//                int x2 = rnd.Next(codeW);
//                int y2 = rnd.Next(codeH);
//                Color clr = color[rnd.Next(color.Length)];
//                g.DrawLine(new Pen(clr), x1, y1, x2, y2);
//            }
            //画验证码字符串 
            for (int i = 0; i < chkCode.Length; i++)
            {
                string fnt = font[rnd.Next(font.Length)];
                Font ft = new Font(fnt, fontSize);
                Color clr = color[rnd.Next(color.Length)];

                g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * codeW / chkCode.Length, (float)0);
            }
            //画噪点 
            for (int i = 0; i < codeW * codeH / 20; i++)
            {
                int x = rnd.Next(bmp.Width);
                int y = rnd.Next(bmp.Height);
                Color clr = color[rnd.Next(color.Length)];
                bmp.SetPixel(x, y, clr);
            }
            //清除该页输出缓存，设置该页无缓存 
            Response.Buffer = true;
            Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
            Response.Expires = 0;
            Response.CacheControl = "no-cache";
            Response.AppendHeader("Pragma", "No-Cache");
            //将验证码图片写入内存流，并将其以 "image/Png" 格式输出 
            MemoryStream ms = new MemoryStream();
            try
            {
                bmp.Save(ms, ImageFormat.Png);
                Response.ClearContent();
                Response.ContentType = "image/Png";
                Response.BinaryWrite(ms.ToArray());
            }
            finally
            {
                //显式释放资源 
                bmp.Dispose();
                g.Dispose();
            }
        }

        //[AllowCrossSiteJson(new[] { "http://localhost:8080" })]
        //public ActionResult Ok()
        //{
        //    return Json(new {code = 200, msg = ""}, JsonRequestBehavior.AllowGet);
        //}
    }
}
